Provide alternative config for netbooting

This change allows to build a customized u-boot image, which includes
networking capabilities, provides diagnostic commands and supports
command line editing. These features are necessary to facilitate the
factory flow.

This image needs to be clearly distinguishable by ChromeOS. This is
achieved by modifying the value presented by the BINF.3 ACPI object.

To build this modified image one needs to add BUILD_FACTORY_IMAGE=1 to
the make invocation line.

BUG=chrome-os-partner:7952
TEST=manual
    . build the new firmware image as follows:

  USE='pcserial factory-mode' emerge-link chromeos-u-boot \
   		 chromeos-coreboot chromeos-bootimage

    . program the new image on the Link target with ChromeOS installed
      on the SSD and restart it
    . observe the target stop at u-boot command prompt (boot >)
    . connect the target to an Ethernet network with a DHCP server
      using a USB Ethernet dongle
    . run the following commands at the u-boot prompt

  boot > usb start
  (Re)start USB...
  USB:   Register 203007 NbrPorts 7
  USB EHCI 1.00
  Register 20400b NbrPorts 11
  USB EHCI 1.00
  8 USB Device(s) found
     scanning bus for storage devices... 0 Storage Device(s) found
     scanning bus for ethernet devices... 1 Ethernet Device(s) found
  boot > dhcp
  Waiting for Ethernet connection... done.
  BOOTP broadcast 1
  BOOTP broadcast 2
  [a few warnings of unsupported DHCP options]
  DHCP client bound to address 172.22.75.25
  Using asx0 device
  TFTP from server 172.16.255.7; our IP address is 172.22.75.25; sending through gateway 172.22.75.254
  Filename 'pxelinux.0'.
  Load address: 0x100000
  Loading: ##
  done
  Bytes transferred = 15840 (3de0 hex)
  boot >

    . start ChromeOS on the target by issuing
  vboot_twostop

    . once ChromeOS boots check the mainfw_type crossystem reported value
  localhost ~ # echo $(crossystem mainfw_type)
  netboot
  localhost ~ #

Change-Id: I1c50517754b6b5f773e432b9adec4b290f303e6f
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/21071
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

3 files changed, 19 insertions, 4 deletions

diff --git a/board/chromebook-x86/coreboot/config.mk b/board/chromebook-x86/coreboot/config.mk
index 857ee8c4b92..627d4cfaf25 100644
--- a/board/chromebook-x86/coreboot/config.mk
+++ b/board/chromebook-x86/coreboot/config.mk
@@ -36,3 +36,6 @@
 
 HOSTCFLAGS_autoconf.mk.dep = -Wno-variadic-macros
 LD := $(LD).bfd
+ifdef BUILD_FACTORY_IMAGE
+PLATFORM_CPPFLAGS += -DFACTORY_IMAGE
+endif
diff --git a/include/configs/coreboot.h b/include/configs/coreboot.h
index fd2c0ccf9fb..939c79a7ffe 100644
--- a/include/configs/coreboot.h
+++ b/include/configs/coreboot.h
@@ -33,10 +33,19 @@
  */
 #define CONFIG_SYS_COREBOOT
 #define CONFIG_SHOW_BOOT_PROGRESS
-#define BUILD_CMD_LINE_STUFF 0
 #define BUILD_IDE_STUFF 0
-#define BUILD_NETWORK_STUFF 0
-#define BUILD_PART_FS_STUFF 0
+
+#ifdef FACTORY_IMAGE
+#define BUILD_CMD_LINE_STUFF 1
+#define BUILD_NETWORK_STUFF  1
+#define BUILD_PART_FS_STUFF  1
+#define CONFIG_BOOTDELAY    -1
+#else
+#define BUILD_CMD_LINE_STUFF 0
+#define BUILD_NETWORK_STUFF  0
+#define BUILD_PART_FS_STUFF  0
+#define CONFIG_BOOTDELAY     0
+#endif
 
 /* FDT support */
 #define CONFIG_OF_LIBFDT	/* Device tree support */
@@ -333,7 +342,6 @@
 
 /* Boot options */
 
-#define CONFIG_BOOTDELAY	0	/* -1 to disable auto boot */
 #define CONFIG_ZERO_BOOTDELAY_CHECK
 #define CONFIG_BOOTARGS		""
 
diff --git a/lib/chromeos/crossystem_data.c b/lib/chromeos/crossystem_data.c
index df387c1484c..f719a29fee9 100644
--- a/lib/chromeos/crossystem_data.c
+++ b/lib/chromeos/crossystem_data.c
@@ -305,7 +305,11 @@ int crossystem_data_update_acpi(crossystem_data_t *cdata)
 	len = min(ID_LEN, sizeof(acpi_table->vbt6));
 	memcpy(acpi_table->vbt6, cdata->readonly_firmware_id, len);
 
+#ifdef FACTORY_IMAGE
+	acpi_table->vbt7 = 3; /* '3' means 'netboot' to crossystem */
+#else
 	acpi_table->vbt7 = cdata->firmware_type;
+#endif
 	acpi_table->vbt8 = RECOVERY_REASON_NONE;
 	acpi_table->vbt9 = cdata->fmap_offset;